Reference

Design

This study was a cross-sectional analysis of an online platform created by the author (Laurie Mischley, ND, PhD). The platform enrolls Parkinson’s patients in a longitudinal research study. The patients self-report their Parkinson’s symptoms, diet diary, and supplement intake.

Participants

The study population included 1,053 people with idiopathic Parkinson’s disease; 93% of the participants were Caucasian, with an average of 5.2 years since diagnosis.

Study Parameters Assessed

Parkinson’s symptoms, progression severity, diet (by recall), and supplement intake; symptoms were assessed using the patient-reported outcomes in Parkinson’s disease (PRO-PD) scale, an outcome tool created by the author.

Primary Outcome Measures

The analysis compared each patient’s rate of disease progression to their diet and supplement intake to search for any statistically significant associations.

Key Findings

The results below show which foods and supplements were significantly (P<0.05) associated with a slowed progression or a more rapid progression of Parkinsonian symptoms.

DELAYED PROGRESSION

MORE RAPID PROGRESSION

Fresh fruits and vegetables

Canned fruits and vegetables

Nuts and seeds

Diet and non-diet soda

Non-fried fish

Fried foods

Olive oil

Beef

Wine

Ice Cream

Coconut oil

Yogurt

Fresh herbs and spices

Cheese

CoQ10

Iron

Fish Oil

Practice implications

Parkinson’s disease is an extremely debilitating condition and is poorly understood.1 Conventional options are limited, and studies suggest that many Parkinson’s patients turn towards diet, natural medicine, and supplements to slow disease progression.2 However, little is known about their efficacy. The present study is an effort to shed light on the effects of diet and supplement use on Parkinson’s disease progression.

Many of the findings of this study are not too surprising. Most of the dietary items associated with delayed progression are elements of a Mediterranean-style diet. This style of eating is anti-inflammatory and has been shown to be associated with fewer cases and later onset of Parkinson’s disease.3 Fish oil has been shown repeatedly to be neuroprotective4 and indeed this study found an association between fish intake and a delayed progression of Parkinsonian symptoms.

Most of the dietary items associated with delayed progression are elements of a Mediterranean-style diet.

The association of consumption of canned foods with a more rapid progression of Parkinson’s disease is intriguing. Because this association persisted after adjustment for income it is less likely to be related to diminished access to health care (which often accompanies low income status). Could there be something in the cans themselves? The authors postulate that bisphenol A (BPA) or aluminum, a known neurotoxin,5 might be contributory.

The association of soda consumption with more rapid progression of disease may be due to specific neurotoxicants, such as aspartame.6 The association with fried foods may be related to lipid peroxidation. The association of ice cream, yogurt, and cheese with rapid progression is consistent with prior research; a meta-analysis of dairy intake and Parkinson’s disease showed an association of dairy intake with Parkinson’s in a dose-dependent manner.7 Both iron supplements and beef, which has a high iron load, were associated with rapid progression in this study, consistent with the suggestion that iron drives symptom progression due to its oxidative nature.8

While coenzyme Q10 (CoQ10) showed early promise in Parkinson’s disease, more recent randomized controlled trials failed to show benefit.9 It is interesting that the association between delayed progression and CoQ10 in this study was no longer statistically significant after adjustment for income. The author postulates that CoQ10, an expensive supplement, might be a surrogate for high income status which itself was associated with a delayed progression, possibly due to better access to health care.

This study has some excellent strengths. The researchers adjusted all results for age, gender, years since diagnosis, and income level, and the results give us some initial clues regarding the effect of diet and supplements on Parkinson’s disease. Of course, there are limitations to this study as well. As a cross-sectional analysis, conclusions from the study design are limited. This study is a longitudinal one and this publication is preliminary and not meant to be exhaustive. Also, the researchers did not correct the P-values for multiple comparisons so it is possible that some statistically significant associations may be spurious.

In summary, this study presents some interesting preliminary findings regarding diet and supplements for Parkinson’s disease. It is an important first step that will be followed up with further work by the study authors and other researchers.

About the Author

Joshua Z Goldenberg, ND is a researcher, teacher, registered naturopathic doctor, and founder of Dr. Journal Club, LLC. He is most passionate about the interplay of evidence and clinical practice.

Goldenberg is an active researcher with numerous publications in high impact scientific journals such as JAMA, Annals of Internal Medicine and The Cochrane Library. His research focus includes irritable bowel syndrome, probiotics, evidence-informed practice, and research methodology. He is currently Research Investigator at the Bastyr University Research Institute and Visiting Research Scholar at the University of Technology Sydney. He has presented nationally and internationally on evidence-based medicine as well as probiotics and research methodology. His probiotics work has been highlighted by the BBC, The New York Times, TheSeattle Times, Prevention Magazine, and Fox News.

Goldenberg is a passionate educator and currently is faculty for the Academy of Integrative Health and Medicine’s Interprofessional Fellowship in Integrative Health and Medicine, where he teaches critical evaluation of the literature and evidence-informed practice. He is past adjunct faculty at Bastyr University, his alma mater, in which he enrolled after receiving honors and distinction in molecular biology from the University of Pennsylvania. He also guest lectures widely.